Method for the manufacture of coated paper



Feb. 11, 1936. D. D. UONG 2,030,483

METHOD FOR THE MANUFACTURE OF COATED PAPER Filed April 1, 1.955 2 Sheets-Sheet l :7, Y ('Y *QQQQ 16 I 2 .9 QQQQOQG J6 Jig/ 57% flab Q0759 Feb. 11, 1936.

D. D. UONG METHOD FOR THE MANUFA C'IURE OF COATED PAPER Filed April l, 1935 2 Sheets-Sheet 2 19% 17502 29 .2. lion 5 Q .w 1 w M 5 6 3 a m, a w m 0 w 3/ .Ww m .a 9

Patented Feb. 11, 1936 um'rse STATES GOA HETHOD FOR THE MANUFACTURE OF PAPER Diong D. Uong, Fitchburg, Mara, assignor to Fitchburg Paper Company, tljlitchburg, Masa, a

corporation of huset Application April 1', ma, Serial No. 663,900

1 Claim. (on. 92-40) This invention relates to the manufacture of paper presenting a coated surface at one or both sides thereof. Such coated papers are commonly produced by the application of a suitable coating material to previously formed paper, and in the usual commercial practice a liquid coating material has been applied to the paper after the paper has been dried and removed from the paper making machine. Such application of liquid coating material to substantially dry paper involves a separate and additional coating operation as well as a second drying operation, all at substantial additional expense.

It is the general object of my invention to pro- 5' duce a coated paper by the application of a coating material in powdered form to a web of paper while it is still in the paper making machine and before the drying thereof is completed.

Preferably I apply the powder to the web at a point where the web still contains a substantial amount of water, a condition found at the suction boxes and to a less extent at the press rolls. It may at times, however, be desirable to apply the powdered coating material even later in the paper making process, as for instance at a point between sections of drying cylinders.

In any event, the powdered coating material is to be applied uniformly to the paper web while it still contains suflicient moisture to enacttive coating on the paper.

A further object of my invention is to provide improved mechanism for thus uniformly applying a powdered coating material to a paper web in a paper making machine.

My invention further relates to arrangements and combinations of parts which will be hereinafter described and more particularly pointed'out in the appended claim. A preferred form of the'invention is shown in the drawings, in which Fig. 1 is a diagrammatic side elevation of portioris of a paper making machine having my in- I vention applied thereto;

Fig. 2 is a sectional side elevation of a preferred form of mechanism for applying the-powdered coating material to the moist webj Fig. 3 is a sectional elevation of the coatingapp'rying mechanism, taken along the line 3-4 in Fig. 2;

Fig. 4 is a detail side elevation of a portion of one of the feeding plates;

Fig. 5 is an end view, looking in the direction 01 the arrowbinFig. 4, and

with the powdered material and produce an effec- Fig. 6 is a detail view, looking in the direction of the arrow 6 in Fig. 5.

Referring to Fig. 1, I have shown portions of a paper making machine of a usual type and having a Fourdrinier section A, a press roll section B and a drying section 0. The Fourdrinier section A comprises a fine mesh wire screen apron or conveyor Ill on which the paper material or pulp is deposited and through which a portion of the water escapes or is sucked away.

The apron HI and partially formed paper web W passes over a series of suction boxes ll, under a dandy roll l2, and around a larger or couch roll H3. The partially formed paper web W then passes between successive pairs of press rolls ll, 13 I5 and IS in the press roll section B, after which ,the web passes around a series of drying rolls or cylinders 20 in thedrying section C, the cylinders 20 being or relatively large size and steamheated to remove a substantial portion of the g0 moisture still remaining in the web W.

The paper-making machine thus briefly described is of a usual commercial type and in itself constitutes no part of my present invention, which relates particularly to the mechanism M for 25 applying coating material in powdered formto the paper web W as it passes through the papermaking machine.

The location of the mechanism M in the papermaklng machine is subject to somewhat wide variation but as at present practiced, I preferably mountthe mechanism M so-that the powdered material is applied to the paper web Was it a passes ovei the first pair of suction boxes H, at which point the paper web may comprise eighty as percent or more of water.

While the position above the suction boxes is at present favored, the mechanism M may, if

desired, be so mounted as to deliver the powdered coating material to the paper web W as it passes through the press roll section B of the machine. Such a location is indicated in dotted lines in Fig. l, the coating mechanism M being positioned to apply the coating material to the web W as it passes from the first pair of press rolls It to the second pair of press rolls It, at which point the web W contains substantially less moisture than at the suction boxes.

I may also position the-coating mechanism entirely beyond the press roll section, as indicated in dotted lines at M in Fig. 1. Under certain conditions it is desirable to locate the coating mechanism between sections of drying cylinders,

as indicated in dotted lines at M in Fig. 1, at

, which point the moisture content of the paper web may be as low as twenty percent.

The location of the coatingmechanism willbe selected with reference to the paper stock, the coating material, the type of surface to be produced, and other operating conditions.

machine at a desired location.

A pair of distributing-mils 24 and 25 are supported in bearings 2' on the frame members 22 and are rotated by the driving. belt. 21 in the direction of the arrows a in Fig.2. 1 A hopper, l0 1 is mounted above the-casing 22' and is provided with feed plates 32, adiustably secured to blocks 34 and 35 which in turn are mounted on pairsof slide bars 36.

The blocks 34 at'each side of the hopper connected by links 40 and 41 to eccentric pins 42 rotated with a pulley 43 by a'belt 44. As the pulley 43 is rotated, it will-be obvious that the feed plates 32am given slight reciprocating. movements in reversed directions, thus tending to evenly distribute ,the powdered material lengthwise of the plates. and to feed the material downward through the relatively narrow opening between the lower edges of the feed plates 22.

The width of this opening may be adjusted by" adjusting the plates 32 in the blocks and I,

for which purpose adjusting screws 4| areprovided. t

The feed plates 32 converge downward as shown in Fig. 2, and the lower edges of the plates are preferably beveled as indicated at46 in Fig. 5 The lower portions of the plates 32 are also preferably grooved as indicated at 41 in Figs. 4 and 6, and the beveled edges 46 are preferably provided with finer grooves as indicated at 48 in'Figs. 4' and 6. As the plates 32 are relatively reciprocated, the grooved lower portions of the plates tend to pulverize the powdered coating material, should any lumps or hard portions occur therein.

By the use of these reciprocating grooved feed plates a fine uniform stream of powdered material is delivered to the roll 24 within the casing 22, and aconsiderable portion of this material is passed along by the roll 24 to the roll 25, as indicated at Fig. 2.

After leaving the roll 25, the powdered material circulates in different directions within the' casing 22 and is finally deposited in a substantially uniform manner on the moist surface of the paper web W. The rolls 24 and 25 are preferably provided with knurled surfaces as indicated in Fig. 3 for moreeifectively advancing and distributing the powdered material.

It will be evident from the foregoing description that the mechanism M for applying the powdered material to the paper web is a selfcontained' unit which may bereadily mounted in any convenient position in a paper-making machine, as indicated at M, M, M and M in Fig. 1, the particular position selected depending onthe nature ofjthe product and desired coating and on the operating conditions.

. It is deemed essential that the paper web should have suilicient substance so that the powdered material will remain largely on the surface of theweb, and'furthermorethat the, web shall con- .tain-suflicient'moisture to coact with the pewdered material inproducing an effective coating. Under -ordinary-conditions the moisture content will run from twenty to ninety percent in the web atthe point ofpowder application.

. The-powdered material itself may be varied to suit operating conditions and the particular type of coating desired, but will commonly consist largely of an adhesive material mixed with some form ofpigment of different colors.

Having thus' described my invention and the advantages thereof, I do not wish to be limited to the detailsherein disclosed, otherwise than as set forth in the claim. but what I claim is:--- t "I'he methodof coating paper which comprises removing a portion only of. the moisture from a paper web in a paper machine having forming wires and a pressing section, applying a coating of moisture-reactive coating material in dry powdered form to the paper web after said web has left the forming wires and at a point adjacent the pressing section, allowing said powdered coating'material to coact with the still substantially moist paper web, and thereafter drying and removing additional moisture from said web and causing said previously powdered material to form a relatively smooth surface on the paper prior to leaving said machine, all of said operations being performed successively. as parts of a continuous paper-making process.

DIONG D. UONG. 

